1. Field of the Invention
The field of the present invention relates to lighting fixtures and associated systems, and more particularly to high efficiency lighting fixtures and associated systems and methods of lighting as may be useful, for example, for motion pictures, television, video, digital image capture, theatre, and the like.
2. Description of the Related Art
Specialized lighting fixtures are often needed in the entertainment industry (including motion pictures, television and theatrical arts, as well as in the photographic industry), as well as in other fields, or in certain commercial, industrial, or consumer settings. In the entertainment industry it is necessary to light a set, stage or other area. To provide highly focused projected light for this purpose, par lamps have occasionally been used. A representative example of such a par lamp is known as the ProCan™ available from TMB of Pacoima, Calif. These par lamps come in several different sizes, such as Par 64 (8″), Par 56 (7″), and Par 46 (5¾″), and typically have, among other things, a standard par light socket, an elongate canister, and a sealed-beam par globe disposed within the canister. These so-called “sealed beam” par lamps (or “cans”) are constructed such that the par globe with its parabolic aluminized reflector, filament and lens are contained in, and operate as, an integrated single unit or lighting fixture. The ProCan par lamp referred to above has a swinging yoke or handle from which it can be hung, for example or mounted on a stand along with a locking assembly. Other models of par lamps used for theatrical lighting and other purposes are made by Altman Stage Lighting Co., Inc. of Yonkers, N.Y. In addition, various companies make smaller par lamps. One such brand sold by TMB Co. is called the ProCan “mini-par” which is, as the name implies, generally a smaller sized version of a larger par lamp.
Attempts have been made to combine par lamps into arrays for the purpose of making lighting units with increased illumination output. One example is the 6×4 Moleeno™ Molepar made by Mole-Richardson Co. of Hollywood, Calif., which uses 24 par-64 (8″) globes. The Moleeno Mole-Par is also made available in other sizes, such as in 6-light, 12-light, 24-light, and 36-light sizes, and is generally constructed of several multi-light sub-assemblies which are combined into a frame to form a larger lighting array.
One drawback of conventional par lamps is that they can use a great deal of power, especially when combined in an array of many lamps. For example, the Molepar mentioned above uses 24,000 Watts at full power which requires 200 Amps. An improved par lamp has become available which offers the potential for increased power efficiency. The basic principles of operation of this improved par lamp are described in U.S. Pat. No. 5,628,213 to Cunningham, hereby incorporated by reference as if set forth fully herein. A commercial version of this par lamp uses HPL lamp elements (as made by General Electric Corporation, for example), and an example is known as the Source Four® par lamp available from Electronic Theatre Controls, Inc. (“ETC”) headquartered in Middleton, Wis. This type of par lamp generally has a concave parabolic reflector configured to be symmetrical about a longitudinal axis, and an incandescent lamp globe or bulb including a plurality of linear helically-wound filaments arranged with their longitudinal axes substantially parallel with, and spaced symmetrically around, the longitudinal axis of the concave reflector. The Source Four type par lamp offers somewhere around a 40% improvement in power efficiency over standard par lamps. However, they are generally quite expensive, heavy, and bulky in nature. A Source Four par lamp has, for example, a sealed reflector housing and numerous heat sink fins cast into the housing. The housing is constructed of rugged, die cast aluminum. The unit contains ten baffles to eliminate beam scattering and spill light. It also has a rugged steel yoke. The size of the unit is 11″ long by 10″ wide, and it weighs approximately eight pounds.
Despite the size and bulk of Source Four par lamps, some recent attempts have been made to combine Source 4 HPL par lamps into larger units. These larger units tend to be heavy and rather expensive. The advertised weight of Source Four par lamps is approximately eight pounds, and thus combining many lamps into large units would result if rather heavy lighting appliances. This can be problematic for use in the entertainment field, where portability and maneuverability are significant concerns.
Another attempt to build a multi-lamp unit based on retrofitted par-type lamp designs has been made, for example, by Bardwell & McAlister Lighting and Grip Inc. of Sun Valley, Calif. These multi-lamp units use part(s) of the ETC Source Four Par lamp (e.g., the Source Four socket retrofitted in a traditional-style Par 64 type multi-par fixture, and the par lamp component(s) are combined with an 8″ reflector and 8″ lens. These retrofitted multi-par fixtures have similar size and, to some extent, weight issues as conventional 8″ (Par 64 style) multi-lamp par fixtures. Although use of a lighter weight aluminum reflector and replacement of some steel parts with aluminum does help to reduce the overall weight somewhat, these lights have other drawbacks. For example, they do not have optimal light output because the HPL components do not match up with the non-HPL components, such as the reflector and lens which are 8″ (Par 64) in diameter, while the HPL bulb is optimized for a 7″ diameter (Par 56) size. Also, these units do not allow convenient replacement of globes. A technician must remove a hot lens (if the lamp has been operating) and attempt to replace the globe from the front, which may require that the technician wait for the lamp to cool down or else expose the technician to some risk of injury, for example.
Par lamps have been used to provide soft, projected diffuse light, as opposed to direct or hard key lighting. A diffusion lighting source can be very useful. Often, particularly for an indoor set in the motion picture and television industries, the key (i.e., primary) lighting is provided at the back corners of the set (opposite where the camera and audience, if any, will be) to avoid boom (sound equipment) shadows and a fill light from the front in accordance with a theory known as back cross key lighting. While back cross key lighting is used, for example, in almost all sitcoms, there are some inherent drawbacks to the approach. One problem is that the “key” or strongest, and often hardest, light comes from the top/back (upstage) portion of the set, so there are invariably shadows thrown from the people and objects on the set onto each other. Also, in many cases there are shadows from a person's facial features that fall upon that person's face, such as nose shadows. The strong (“hard”) light coming from the back also creates hot rims around people and is especially objectionable on bald or light-haired individuals. This hard light, which has been traditionally used, can also create unwanted microphone boom shadows. These back cross key lights traditionally used are Fresnels, which are “hard” lights. Because of the inherent inefficiency in the design of the reflector and Fresnel lens, the output of these instruments if softened substantially with one or more moderate or heavy diffusion filters placed in front of the light results in very poor output versus amperage drawn.
Conventional wisdom is that the lights are mounted on a stand, on a pipe, or on typical set scaffolding known as a green bed. As there are numerous lights on a set, and as providing a diffusion screen on each light is cumbersome, and as it is further cumbersome to change such screens and to align such lights to properly cooperate, the use of individually mounted diffusion devices is not practical or economical for some set lighting especially sitcoms. Examples of individually mounted diffusion gel supporting members are shown in U.S. Pat. No. 5,651,602 to Joseph N. Tawil, issued Jul. 29, 1997, and U.S. Pat. No. 4,446,506 to Raymond G. Larson issued May 1, 1984. These require special brackets or rings to mount to the lighting instrument, and are often dependent on the type of light.
A diffusion device has been known to be used with multiple lights, such as in U.S. Pat. No. 4,855,874 to Thomas A. Waltz issued Aug. 8, 1989. The Waltz patent discloses a light modifier which is inflatable and surrounds multiple lights attached to a stand or to other support rods which are not part of the inflatable device. The device itself which provides light diffusion must be entirely changed to change the light diffusion effect, and it has limited ability to control and direct light. It is therefore impractical to use for set lighting. Moreover, it requires a pump to maintain the inflatable device, which can be noisy and thus could interfere with shooting television or motion pictures.
Even when diffusion is used, often expensive Fresnel lights are used with it. These lights are generally focusable between “spot” and “flood” conditions, and provide a useful light source because one can adjust the pattern and intensity of the light when it is not heavily diffused, allowing for a tight “spot” of hot light, a wide flood of lesser intensity, or a selectable middle ground. It is interesting to note that when projected through heavy diffusion, this function is neutralized. Fresnel lights also have other drawbacks; for example, they are generally expensive, inefficient, heavy and cumbersome.
One of the needs in the industry is for a versatile, lightweight and compact lighting apparatus which can diffuse and control light from multiple lights in such a way that the lights are stable, while preferably avoiding the need for expensive lighting instruments such as Fresnel (focusable) lights, and provide a soft, even diffused light for purposes such as key or primary lighting for a stage or set. What is also needed is a device that can project soft light in a controllable way deep into the set evenly from front to back and side to side while having a compact profile to allow for, e.g., cameras underneath and viewers behind. The light could be made to be parallel to and under the microphone booms thus eliminating boom shadows. The light could also be made to come from a similar angle as the cameras eliminating or “burying” shadows behind the objects themselves.
Certain light fixtures have been made for overhead lighting, i.e., above a set or other item needing light. However, many such fixtures generally do not provide an efficient soft projected and consistent light. For example, one configuration known as the “chicken coop” has six 1000-watt bulbs shaped much like household bulbs. These contraptions were originally designed with silver tip bulbs which are opaque on half the round portion of the globe, so that when illuminated in a downwards position the light energy would be directed at the interior roof of the “coop” thus creating a bounced light that is quite inefficient versus amperage drawn. When used with more standard globes (such as 1000 Watt mogul base bulbs without the “silver tip”), the light is unevenly pushed through the lamps themselves and bounced off the light shell, resulting in a very mixed source with limited projection. The color temperature of the bulbs is not ideal for motion picture and other photographic purposes; thus, the interior of the chicken coop unit which acts as the reflector is commonly painted a light blue to “cool off” the warm bulbs. This not only reduces reflection efficiency, but it also causes a different color temperature light to be emitted from the unit, since the reflected light is colder than the direct light when using non silvertip globes. Even if a diffusion screen is used, the light is inconsistent and the bulbs cannot be individually controlled in a traditional chicken coop configuration. Also, sound can be an issue, as dimming of these lamps often results in creation of a hum or noise which is unsuitable for filming with synchronized (live capture) sound.
Sometimes, a long cylindrical fabric sheath with a roughly 30-inch diameter opening is placed around some open globes in a wheel-type configuration known as a “space light.” The sides of the sheath can be blackened. One problem with the space light as an overhead light source is that it uses quite a bit of energy for relatively little output. Much of the light is absorbed in the black sheaths and thus does not get transmitted from the opening at the bottom of the sheath. The internal source, being merely globes (and a very narrow strip flat reflector), is not internally or externally focused to project very well through the exit port in the space light. Even when used without the black sheaths, the light output and range of projection is still unimpressive in view of the amount of amperage drawn. The quality of the space light (in terms of softness/color) cannot be easily customized; moreover, multiple shadows are typically created from the space light, and the lamp life is short.
Light diffusion contraptions have been constructed of cardboard or other consumables in a jury-rigged fashion for a long time. Also, a company known as Chimera Lighting of Boulder, Colo., markets among other things cone-shaped soft tent-like members for attachment in front of a lighting source, typically a single Fresnel light.
Recently, a multi-par “soft light cannon” for projecting diffused light has been the subject of patents including U.S. Pat. Nos. 6,106,125, 6,588,912, and 6,719,434. A commercial embodiment thereof, known as the Toplight™ lighting fixture manufactured by FinnLight, Inc. of Malibu, Calif., includes a housing and a fixture that can contain six 1000-Watt Par 64 lamps directed at one or more diffusion element(s) for providing a deeply projected soft light. Another product by FinnLight is the TopBox™ lighting fixture, which is a foldable box with a diffusion element. Up to ten large standard (i.e., Par-64) par lamp cans may be incorporated therein for creating a deeply projected soft light. A lightweight version of the TopBox™ lighting fixture, with an aluminum frame and up to ten standard par lamp cans, is also commercially available. The Maxilight™ 4 k lighting fixture is a four par lamp version designed to incorporate the characteristics of four 1000 w Par 64 lamps while built into a lightweight and well ventilated aluminum housing. A detachable aluminized Nomex™ housing (soft box) with multiple spaced diffusion frames allows for precise control and variable quality of deeply projected and tightly controlled softlight. Soft or hard grids can be utilized on the exit port of this light to further tighten the beam angle of this Soft, projected light source. While the TopLight™, TopBox™ and Maxilight™ 4 k represent significant improvements over the state of the art, it would be advantageous to provide variations thereof that are specifically adapted for particular environments or contexts. For example, high definition television (HDTV) is a relatively new medium that presents challenges because the picture quality is much sharper than conventional television. Some surprised HDTV consumers have tuned in their favorite newscaster only to see less than flattering features due to inappropriate conventional lighting on this sharper display medium. Hence what would be useful for HDTV settings is a softer, more deeply projected and controllable light. In other contexts as well it would be desirable to have soft, projected light created quickly, safely and efficiently to address the evolving needs of new capture and display mediums such as HDTV.
In addition, the amount of lighting, including soft illumination, needed during a film or television shoot varies depending upon the requirements of particular scenes and various factors such as the location, size of the set or stage, available natural lighting, and so forth. At the same time, the amount of room available for lighting may be limited. Such constraints may exist both with diffusion and non-diffusion lighting sources. It would therefore be advantageous to provide an integrated, lightweight lighting apparatus that is flexible, allowing for a variety of options including, e.g., a more precise and controllable light characteristic, which can provide varying degrees of illumination, in a cost effective manner, with a high efficacy (output per watt) and be as compact as possible both in use and for shipping/storage.